Kil-Sang Yoo Mi-Ae Kim Won-Hyung Lee A Robust Image Watermarking Technique for JPEG Images Using QuadTrees. 34-41 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3332&spage=34 2004 conf/pcm/2004-2 PCM (2) db/conf/pcm/pcm2004-2.html#YooKL04